The present invention is related to multifrequency, flush mounted antennas and, more particulary, is directed towards dual frequency antennas which are designed into the structure of a conical dielectric radome.
Necessarily, antennas are designed to perform a required electrical function, for example, transmitting or receiving signals of a desired bandwidth, direction, polarization, gain, or other relevant characteristics. However, often mechanical restrictions such as size, weight, location, and profile are just as important or more important considerations, especially when the electrical parameters would conventionally require wave guides that are bulky and heavy. This is the case for many missile systems, aircraft, reentry vehicles, and various projectiles. Low profile, ring, and wraparound conformal antennas are several solutions that provide some relief to these often vexatious considerations.
When a radome or similar structure is used to house the essential guidance or fuzing system the above solutions often do not provide a satisfactory answer, especially when dual frequency capabilities are required. Robert Pierrot in U.S. Pat. No. 3,864,690 incorporates into such a radome a dual frequency antenna by utilizing a dielectric whose thickness is transparent to a first frequency and a network of wires integral with the dielectric designed to be transparent with a second frequency. The system also includes a network of discontinuous elements to compensate for grating lobes originating from the network of continuous wires.
Robert Munson in U.S. Pat. No. 3,811,128 is pertinent in illustrating a microstrip antenna which can be mounted on the vehicular skin of an airplane or missile. This antenna system does not suggest the dual frequency capability of the Pierrot patent, yet is simpler in design and cheaper to build than the Pierrot patent.
What this invention is directed towards is an antenna system which combines the qualities of these two inventions into one superior, easy to build antenna system.